Conventionally, the air/fuel mixture required for the operation of a gasoline engine is supplied to the gasoline engine via a so-called suction manifold. The formation of the air/fuel mixture frequently takes place within the suction manifold with the aid of one or a plurality of suitable injection valve(s) (so-called manifold injection).
During operation of such, a gasoline engine fuel may deposit on the inner wall of the suction manifold as a function of an instantaneous operating state, this process being referred to as wall film buildup. In another operating state the deposited fuel may then be broken down again, which is referred to as wall film breakdown. The effect of the wall film buildup and wall film breakdown is referred to as wall film effect.
The wall film effect manifests itself especially clearly during load changes. In an increase of the load, denoted as positive load change, the pressure in the suction manifold rises, so that more fuel is deposited on the inner wall of the suction manifold. In a negative load change, i.e., when the load is reduced, the pressure in the suction manifold decreases, which causes the wall film to be broken down.
The control and regulation of the gasoline engine includes, in particular, measures for providing the instantaneously required air-fuel mixture. However, since the air-fuel mixture supplied to the combustion is influenced by wall film effects, the wall film effect occurring during the load change is compensated for by a corresponding functionality of the control device with the aid of a so-called transition compensation, so as to allow an operation of the gasoline engine that is always optimized with regard to the exhaust gas.
The effectiveness of the transition compensation depends on a multitude of factors, such as the quality or the composition of the fuel used at the moment, as well as the type and age of individual components of the gasoline engine, for instance the injection valves. If a transition compensation is applied for the control and regulation of a particular gasoline engine, then the implementer presently checks the effectiveness of the transition compensation based on a few load changes. The implementer then decides whether or not a calibration of the transition compensation is necessary. Following a calibration, the effectiveness of the transition compensation is checked anew, if appropriate, based on individual load changes, and recalibrated. This method is repeated until the effectiveness of the transition compensation is considered sufficient by the implementer.
This method is very time-consuming. Furthermore, the quality of an application generally depends on the implementer's empirical values.
During an application of the transition compensation, load change measurements are performed both on a test stand and also during road operation. In order to check the effectiveness of the transition compensation in as many operating points as possible, the load changes must be monitored at a multitude of different engine temperatures and engine speeds. Observed deviations of the air-fuel mixture (so-called Lambda deviation) are then checked by the implementer and evaluated.
The evaluation is based on the implementer's subjective experience. As a result, the quality of a transition compensation or a calibration is decisively determined by the experience and the subjective evaluation of the implementer. Due to the considerable time and manpower required and the often less than optimal evaluation by the implementer, the transition compensation is often not optimally effective.